My buddy picked up a Gorgar a couple months ago and it was working fine until recently when the sound stopped working. In troubleshooting, here's what they've found:

Solenoid test produces no sounds when 9-13 are triggered.

Pressing test button on sound board will begin making sounds, though speech is sometimes rather static-y. Wiggling ribbon cable between sound and speech boards seems to cause sound and speech to cut in/out and makes the static come and go.

Driver board connector for sound triggers has a new male and female connector installed.

I got the board from him to try to diagnose further at home. Can i test the Gorgar sound boards in my Black Knight?

Suggestions?

Thanks!

Good to know! Just wasn't sure if there was any conflicts using the same sound board between a system 6 game and system 7 game, or if it needed any jumpers run or removed etc.

I'll try it in my BK later and report back with more info. One thing i caught so far, this 1000uf cap looks like it's been leaking, perhaps? No residue on the board, it appears self-contained. For all i know, that could be normal appearance for these caps. I'll be changing it, but I'm curious if that would contribute to any of the problems I'm having. I'll test it with my cap tester once i pull it out, too.

IMG_20201221_092458.jpg

While we're talking caps, i noticed the sound board has the big cap on the lower-right replaced already, with a 4700uf cap. Looking at the schematic, it calls for a it 12,000uf cap. Which is correct?

IMG_20201221_110650.jpg

Thanks for the insight, @MarAlb, @Jjsmooth, and @slochar--and good eye @grumpy!

I went ahead and put the Gorgar sound board in my Black Knight and got no sound in the coil test though everything else still works fine. Test button on the sound board did not cause any sounds or speech. So the game is silent with the Gorgar board installed as-is. I'll check voltages at the board next and see what's shaking there. Next step will be to replace the caps on the board. Any other suggestions?

Thanks!

Just tried it in gameplay, sound test, and tried the test button on the sound board--still no sound at all. Twisted the volume pot in the cab back and forth, still nothing. Also tried sound/speech mixer pot and nothing there either.

I checked voltages at the test points on the sound board, here's what i have:

TP1 12.9 VDC
TP2 -14.1 VDC
TP3 ground
TP4 5.08 VDC

Voltages all appear to be in spec, and i triple-checked my connectors to be sure everything's hooked up correctly. I'll try putting my BK sound board back in and verify that it's still working to rule out anything else.

Sorry--to clarify: since installing the Gorgar sound board in my BK for testing, it has so far produced no sounds at all.

THANK YOU, @MarAlb!

I decided to try swapping the 6808 from another sound board i had laying around for parts (a Motorola chip, at that)... and we now have sound and speech, and it's clear too.

I've gotta say, Black Knight is actually kinda cool with Gorgar sounds

I'm gonna go ahead and replace those bad looking caps (there's actually 3 of those silver caps on the board and they're all showing that brown stuff coming out the ends). I'll get the board to my buddy asap and have him try it out.

I'll report back with a final update when it's working in his game (hopefully!)

Thanks again to everyone who chimed in here!

Just to bring this to a conclusion: Gorgar's sound and speech is now working properly in my buddy's game since replacing the 6808. Thanks again for the help everyone!